If they get full 48 minutes (48.00 minutes which is shown as 48+ on Manage My Team page), they get full training. If they get less, they don't.
The 48 vs. 48+ issue is about the training summary on Manage My Team page. The weekly stats on the other hand do not have the + sign. There 48.00 or, say, 48.15 minutes (both of which are 48+ and give full training) are shown as 48. However, 47.45 which doesn't give quite full training is also shown as 48. If you want to be 100% sure, check the Manage My Team page.